Static frequency multiplying system



July 5, 1966 P. P. BIRINGER 3,259,828

STATIC FREQUENCY MULTIPLYING SYSTEM Filed 0G13. 26, 1961 I NVEZUTOR. Paul H enrayer Jimmy@ United States Patent 3,259,828 STATIC FREQUENCY MULTIPLYING SYSTEEM Paul Peter- Biringer, Toronto, Ontario, Canada, asslguor to Ajax Magnethermic Corporation, Youngstown, Ohio, a corporation of Ohio Filed Oct. 26, 1961, Ser. No. 147,969 5 Claims. (Cl. 321-7) My invention relates to a static frequency multiplying system and relates more particularly to improvements in a symmetrical frequency multiplying system wherein means `are employed for stabilizing .the system consisting of reactors having a. current-voltage relationship which is linear throughout the operating range` of the system, as set forth in co-pending applications for U.S. Letters Patent, Serial Nos. 713,343 and 725,004, tiled February 7, 1958, and March 31, 1958, which issued into United States Letters Patent No. 3,040,230 and No. 3,040,231 dated June 19, 1962, respectively.

In such systems a multiphase source, such as a threephase source of alternating current, energizes current dependent inductances, i.e. primaries normally connected in star relation to a star connection point, the said current dependent inductances or primaries are separated from the source terminal by said reactors, condensers are effectively connected to the primaries either in Y or delta form and said condensers are supplied with nonsinusoidal voltage developed phase to phase between the reactors and the non-linear primaries.

The present improvement consis-ts in providing means for selecting ydesired values for the non-sinusoidal voltages supplied to the condensers.

It is an object of my invention to provide improved means associated with the non-linear inductances or primaries of the system referred to, which are simple in construction and readily incorporated in said primaries and which, without altering the essential non-linear characteristicsI of such primaries, produce an auto-transformer effect in the system so that the value of the non-sinusoidal voltages supplied to the -condensers may be different from values of the non-sinusoidal voltage appearing across the junctures between the so-called linear reactances and said current depending inductances, viz. primaries.

It is a further object of my invention to provide by the utilization of much improved means in connection with the non-linear primary structures a more economical construction of condensers without loss in operating eiiiciency.

A further advantage resides in the fact that when the improved means of my invention are used to increase the voltages as applied to the condensers, it is possible to reduce the cross-section at once of the conductors used in the windings in the non-linear inductances, thereby achieving a relative reduction in eddy current losses in said conductors and a resulting improvement in the overall efficiency.

Other objects of the invention and the invention itself will be more readily appreciated by reference to the appended description rand drawings, in which drawings:

FIG. 1 is an electrical schematic View of a preferred power system for connecting a multiphase power source to single phase high frequency power output for induction heating service;

FIG. 2 is an electrical schematic view of another embodiment of my invention.

The system of the invention as shown in the drawings submitted herewith discloses a multiphase source, such as a three-phase source of alternating voltage de livered from terminals 10, 11, and -12 energizing current dependent inductances, i.e. primary structures 13, 14, and 15 connected in star arrangement, the primaries being 'separated from the terminals by reactances 16, 17, and 18 for the current which reactances may be furnished "ice in the form of chokes having an air gap (not shown).

The primary structures shown consist of windings 413a and 13b, 14a and 1-4b, 15a and 15b of diierent leakage reactance. Each said reactance serves to connect the respective primaries to their respective source and serves also to isolate the source from harmonic currents reected by the primaries. The reactances 16, 17, and 18 have, in the form shown, a current-voltage relationship which is linear, developing non-sinusoidal voltages across the junctures between the reactors and the primary structures and provide a high impedance path for harmonic components .of said frequency reliected by the primary structures.

Condensers 20, 21, and 22 .are effectively connected to the primaries either in Y, in which case the star point should not be grounded, or delta, the delta connection being shown. lt is to be noted that the connection of the condensers to the primaries are at a point on the primary windings where the leakage reactances of the windings are different from the point at which the linear reactances are connected to said windings. Said condensers provide Ia low impedance path for harmonic currents passing non-sinusoidal current to the primaries. Each of the linear reactances 16, 17, and 18 are connected to Ia selected point on the said primary windings so that each respective linear reactance is interposed between each said primary and its terminal source.

By properly selecting the turn of the respective primary winding, as by a tap connection, etc., to each of which a linear reactance and condenser are connected, the value of non-sinusoidal voltages delivered to the condensers can be controlled to any desired value. The importance of this control of the value of the voltage delivered to the condensers lies in the `fact that it enables a more economical design of the condensers than would be possiblewith the connections shown in the prior applications to which reference has been made.

When the selected connection is made as described above, 'and the condensers are connected at a point equivalent to an extension of the primary winding, a reduction of the cross-sectional area of Ithe conductors used in the primary windings may be and is preferably made whereby the relative eddy current losses are reduced with an improvement in the overall efficiency. The connection illustrated, which is made as above discussed, enables the values of the non-sinusoidal voltages delivered to the condensers to be adjusted to a different value from that present Iacross the junctures of the linear reactances and the primaries, without, however, affecting the non-linear characteristics of the primaries and without affecting the symmetry of the system adversely in any way.

In the form of my invention shown in FIG. 1, I have shown secondaries 30, 31, and 32 connected in series and magnetically coupled to the primary windings 13, 14, and 15 by cores 33, 34, and 35 which in tu-rn are connected to the load indicatedl at A-B. It will be understood that secondary windings such as 30, 31, and 32 are notessential to the operation of the system and it will be apparent to those skilled in the art that :arrangements such as shown in FIG. 2 could be utilized to deliver the desired harmonic frequency output.

In either form, the voltage across the terminals A-B will lbe a harmonic `of the source and the power delivered will be single phase distributed symmetrically lacross the primaries and a substantial unity power factor is achieved at the source.

While I have described my invention in connection with several preferred embodiments thereof, I am aware that departures may be made therefrom, such as providing separate conductors of different cross-sectional area for the portions A13a and 13b, 14a and 14h, 15a and 15b, respectivefly, with a resultant reduction in eddy losses in spsaeae 3 the section of lesser cross-sectional area in the portions 13b, 14h, and 15b, but without, however, departing from the spirit of my invention or the scope of the 'appended claims.

What I claim is:

1. A power supply system comprising a multiphase source `of alternating voltage of sinusoidal form land predetermined frequency 'and adapted to deliver single phase power of ythe harmonic frequency of the source symmetrically distributed with respect to said source, a primary structure for each phase of said source energizable by the latter having a current volt-age relationship which is non-linear for each phase of said source and consisting of windings of different leakage reactance; a reactance having `a current voltage relationship which is linear disposed between said primary structure and said source; said linear reactances developing non-sinusoidal voltages across the junctures of said linear reactances and s-aid primary structures; condensers interposed between said primary structures; means associated with each of said prim-ary structures whereby the v-alue of voltages supplied to said condensers is caused to Adiffer from those values of voltages appearing across the junctures of said linear reactancesland said primary structures while preserving the non-linear characteristics of said primary structures.

2. A power supply system comprising a Imultiphase source of alternating voltage of sinusoidal form and predetermined frequency and adapted to deliver single phase power of the harmonic frequency of the source symmetrically distributed with respect to said source, a primary structure for each phase `of said source energizable by the latter having a current voltage relationship which is nonlinear for each phase of said source; a reactance having a current voltage relationship which is linear disposed between said primary structure and said source; said linear react-ances developing non-sinusoidal voltages across the juncturesof said linear reactances and said primary structures; condensers interposed between said primary structures passing non-sinusoidal current -to said primary struc- `tures; selecting means associated with each of said primaryv structures whereby the value of voltages supplied to said condensers is caused to differ from those Values of voltages appearing across the junctures of said linear reactances and said primary structures while preserving the non-linear characteristics of said primary structures, means t-o obtain harmonic frequency power symmetrically distributed with respect to said source.

3. A power supply system comprising a multiphase source of alternating voltage of sinusoidal form and predetermined frequency and adapted to deliver single phase power of the harmonic frequency of the source symmetrically distributed with respect to said source, a primary structure for each phase of said source energizable by the latter having a current voltage relationship which is non-linear for each phase of said source; a reactance having a current voltage relationship which is linear disposed between said primary structure and said source; said linear reactances developing non-sinusoidal voltages across the junctures of said linear reactances and said primary structures; condensers interposed between said primary structures passing non-sinusoidal current to said primary structures; means associated with each of said primary structures whereby the value of voltages supplied to said condensers -is caused to differ from those values of voltages appearing across the junctures of said linear reactances and said primary structures while preserving the non-linear characteristics 4of said primary structures; second-ary windings for each primary structure magnetically coupled to the latter; and means connecting said secondary windings electrically in series thereby to obtain a single phase harmonic lfrequency power symmetrically distributed with respect to said source, the relationship between the reactances and condensers being such that a substantial unity power factor is achieved at the source.

4. A power supply system comprising a multiphase source of alternating voltage of sinusoidal form and predetermined frequency and adapted to deliver single phase power of the harmonic frequency of the source symmetrically distributed with respect to said source, a primary structure for each phase of said source energizable by the latter having a current voltage relationship which is non-linear for each phase of said source and consisting of windings of different leakage reactance; a reactance having a current voltage relationship which is linear disposed between said primary structure and said source;

`said linear reactances developing non-sinusoidal voltagesV across the junctures of said linear reactances and said primary structures; condensers interposed Ibetween said primary structures; said condensers being connected through a winding of said primary structures of different leakage reactance than the remainder of the primary connected to the juncture of said linear reactance and said primary whereby the value of voltages supplied to said condensers is caused to differ from those values of voltages 'appearing across the junctures of said linear reactances and said primary structures while preserving the nonlinear c-haracteristics of said primary structures.

S. In a system as claimed in claim 2, characterized by each of said primary windings consisting of a pair of windings, each set of said windings being of different cross-sectional area, the said selecting means increasing the value of the voltages supplied to said condensers to a predetermined value above the values of the voltages appearing across the junctures whereby eddy current losses corresponding to the harmonic distribution of currents in said windings `approaches a minimum.

References Cited by the Examiner UNITED STATES PATENTS 2,377,152 5/1945 Huge.

2,424,236 7/1947 Huge a 321-69 2,451,189 10/1948 Alexanderson 321-69 2,727,159 1271955 Sunderlin 321-69 3,188,550 6/1965 Hauck 321-68 y LLOYD McCoLLUM, Primary Examine?.

G. I, BUDOCK7 G. GOLDBERG, Assistant Examiners. 

3. A POWER SUPPLY SYSTEM COMPRISING A MULTIPHASE SOURCE OF ALTERNATING VOLTAGE OF SINUSOIDAL FORM AND PREDETERMINED FREQUENCY AND ADAPTED TO DELIVER SINGLE PHASE POWER OF THE HARMONIC FREQUENCY OF THE SOURCE SYMMETRICALLY DISTRIBUTED WITH RESPECT TO SAID SOURCE, A PRIMARY STRUCTURE FOR EACH PHASE OF SAID SOURCE ENERGIZABLE BY THE LATTER HAVING A CURRENT VOLTAGE RELATIOHSHIP WHICH IS NON-LINEAR FOR EACH PHASE OF SAID SOURCE; A REACTANCE HAVING A CURRENT VOLTAGE RELATIONSHIP WHICH IS LINEAR DISPOSED BETWEEN SAID PRIMARY STRUCTURE AND SAID SOURCE; SAID LINEAR REACTANCES DEVELOPING NON-SINUSOIDAL VOLTAGES ACROSS THE JUNCTURES OF SAID LINEAR REACTANCES AND SAID PRIMARY STRUCTURES; CONDENSERS INTERPOSED BETWEEN SAID PRIMARY STRUCTURES PASSING NON-SINUSOIDAL CURRENT TO SAID PRIMARY STRUCTURES; MEANS ASSOCIATED WITH EACH OF SAID PRIMARY STRUCTURES WHEREBY THE VALUE OF VOLTAGES SUPPLIED TO SAID CONDENSERS IS CAUSED TO DIFFER FROM THOSE VALUES OF VOLTAGES APPEARING ACROSS THE JUNCTURES OF SAID LINEAR REACTANCES AND SAID PRIMARY STRUCTURES WHILE PRESERVING THE NON-LINEAR CHARACTERISTICS OF SAID PRIMARY STRUCTURES; SECONDARY WINDINGS FOR EACH PRIMARY STRUCTURE MAGNETICALLY COUPLED TO THE LATTER; AND MEANS CONNECTING SAID SECONDARY WINDING ELECTRICALLY IN SEREIS THEREBY TO OBTAIN A SINGLE PHASE HARMONIC FREQUENCY POWER SYMMETRICALLY DISTRIBUTED WITH RESPECT TO SAID SOURCE, THE RELATIONSHIP BETWEEN THE REACTANCES AND CONDENSERS BEING SUCH THAT A SUBSTANTIAL UNITY POWER FACTOR IS ACHIEVED AT THE SOURCE. 